A technique is generally known that, in order to meet control specifications for a control device for a moving object, configures a feed-forward control method by applying a control method with two degrees of freedom to a feedback control system. In particular, a feed-forward control method for a mechatronic device that has a high-order resonance mode requires a technique for arriving at a target position within a required target positioning time without exciting a high-order vibration mode.
In Japanese Patent Application Publication No. JP-A-2001-249702, a technique for this purpose is disclosed that, by using multiple rates for a control input cycle, combines an inverse model design and a target path design that takes vibration suppression into account. In a positioning control device for a moving object, in a case where a positioning operation is performed in a frequency band that is close to a resonant frequency, it is essential to generate a control input that suppresses the resonant frequency and a high-frequency component. However in the case of the present technique, a problem occurs in that the target path must be designed in advance, which is impractical, because it makes it impossible to assign the target path freely.
Therefore, in Japanese Patent Application Publication No, JP-A-08-255023, Japanese Patent Application Publication No. JP-A-2007-200463, and Japanese Patent Application Publication No. JP-A-2004-272883, a technique is proposed by which a feed-forward control is performed by inputting a position command path to a digital filter. Further, in Japanese Patent Application Publication No. JP-A-08-255023, a technique is disclosed that speeds up convergence on the target position by determining a factor in a polynomial expression for the digital filter by minimizing an evaluation function, and that shortens the positioning time by improving a transient response.